U.S. patent application number 10/825657 was filed with the patent office on 2004-12-02 for method for forming liquid crystal display comprising manufacturing light-shielding film by applying coating liquid containing fine metal particles onto substrate and drying the same.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Gotoh, Hidenori, Hatakeyama, Akira, Ito, Hideaki.
Application Number | 20040239842 10/825657 |
Document ID | / |
Family ID | 33447063 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040239842 |
Kind Code |
A1 |
Hatakeyama, Akira ; et
al. |
December 2, 2004 |
Method for forming liquid crystal display comprising manufacturing
light-shielding film by applying coating liquid containing fine
metal particles onto substrate and drying the same
Abstract
The present invention provides a method for forming a liquid
crystal display comprising: providing a liquid crystal display
substrate; and forming a light-shielding film for a display on the
liquid crystal display substrate by coating the liquid crystal
display substrate with a coating liquid containing a binder and
fine metal particles, such as fine silver particles, dispersed in
the binder, and optionally a dispersant by use of a spin coat
method, a curtain coat method, or an extrusion method, and drying
the resultant layer, and optionally forming a protective layer on
the layer and exposing the protective layer to light.
Inventors: |
Hatakeyama, Akira;
(Shizuoka-ken, JP) ; Gotoh, Hidenori;
(Shizuoka-ken, JP) ; Ito, Hideaki; (Shizuoka-ken,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
|
Family ID: |
33447063 |
Appl. No.: |
10/825657 |
Filed: |
April 16, 2004 |
Current U.S.
Class: |
349/110 |
Current CPC
Class: |
G02F 1/133512 20130101;
C09K 2323/06 20200801; C09K 2323/00 20200801; C09K 2323/05
20200801; Y10T 428/25 20150115 |
Class at
Publication: |
349/110 |
International
Class: |
G02F 001/1333 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2003 |
JP |
2003-113612 |
Claims
What is claimed is:
1. A method for forming a liquid crystal display comprising:
providing a liquid crystal display substrate; and forming a
light-shielding film for a display on the liquid crystal display
substrate by coating the liquid crystal display substrate with a
coating liquid containing a binder and fine metal particles
dispersed in the binder, followed by drying.
2. A method for forming a liquid crystal display according to claim
1, wherein the fine metal particles in the coating liquid are
dispersed with a dispersant.
3. A method for forming a liquid crystal display according to claim
2, wherein the dispersant includes at least one of a surfactant and
a polymer.
4. A method for forming a liquid crystal display according to claim
3, wherein the amount of the surfactant used is 0.01 to 30% by
weight relative to the fine metal particles.
5. A method for forming a liquid crystal display according to claim
3, wherein the amount of the surfactant used is 0.1 to 20% by
weight relative to the fine metal particles.
6. A method for forming a liquid crystal display according to claim
3, wherein the amount of the polymer used is 0.01 to 30% by weight
relative to the fine metal particles.
7. A method for forming a liquid crystal display according to claim
3, wherein the amount of the polymer used is 0.1 to 20% by weight
relative to the fine metal particles.
8. A method for forming a liquid crystal display according to claim
1, wherein the fine metal particles are fine particles of nickel,
silver, gold, platinum, copper or an alloy thereof.
9. A method for forming a liquid crystal display according to claim
1, wherein the fine metal particles are fine silver particles.
10. A method for forming a liquid crystal display according to
claim 1, wherein the average particle diameter of the fine metal
particles is 1 to 3000 nm.
11. A method for forming a liquid crystal display according to
claim 1, wherein the average particle diameter of the fine metal
particles is 10 to 250 nm.
12. A method for forming a liquid crystal display according to
claim 1, wherein the liquid crystal display substrate is coated
with the coating liquid containing the binder and the fine metal
particles by a spin coat method, a curtain coat method, or an
extrusion method.
13. A method for forming a liquid crystal display according to
claim 1, wherein a protective layer is disposed on the
light-shielding film for a display, and exposing the protective
layer to light.
14. A method for forming a liquid crystal display comprising:
providing a liquid crystal display substrate; and forming a
light-shielding film for a display on the liquid crystal display
substrate by coating the liquid crystal display substrate with a
coating liquid containing a binder, fine metal particles dispersed
in the binder and a dispersant, followed by drying.
15. A method for forming a liquid crystal display according to
claim 14, wherein the dispersant includes at least one of a
surfactant and a polymer.
16. A method for forming a liquid crystal display according to
claim 15, wherein the amount of the surfactant used is 0.01 to 30%
by weight relative to the fine metal particles.
17. A method for forming a liquid crystal display according to
claim 14, wherein the amount of the polymer used is 0.01 to 30% by
weight relative to the fine metal particles.
18. A method for forming a liquid crystal display according to
claim 14, wherein the fine metal particles are fine silver
particles.
19. A method for forming a liquid crystal display comprising:
providing a liquid crystal display substrate; and forming a
light-shielding film for a display on the liquid crystal display
substrate by coating the liquid crystal display substrate with a
coating liquid containing a binder, fine metal particles dispersed
in the binder and a dispersant, drying an obtained layer, forming a
protective layer on the obtained layer, and exposing the protective
layer to light.
20. A method for forming a liquid crystal display according to
claim 19, wherein the fine metal particles are fine silver
particles.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. 119 from
Japanese Patent Application No. 2003-113612, the disclosure of
which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method for forming a
liquid crystal display including a color filter with a
light-shielding film.
[0004] 2. Description of the Related Art
[0005] A light-shielding film is a black edge portion formed, in
order to prevent light from leaking, around red, blue and green
pixels of a color filter and around the color filter, and a
dot-like or linear black pattern for shielding a thin film
transistor (TFT) from light.
[0006] In a color filter used in a color liquid crystal display,
pigmented pixel layers having red (R), green (G) or blue (B) color
are formed on a transparent substrate. Moreover, in order to
improve display contrast, a light-shielding film for a display is
formed in gaps between the respective pigmented pixels of red,
green and blue. In particular, in a liquid crystal display element
of an active matrix drive system that includes a thin film
transistor (TFT), in order to prevent image quality from
deteriorating owing to an electric current leakage in the thin film
transistor caused by light, the light-shielding film for a display
is required to have high light-shielding property (optical
density).
[0007] In order to manufacture a light-shielding film for a display
with high light-shielding property, usage of metal has been
considered. As a technique for manufacturing a light-shielding film
for a display using fine metal particles, a technique for
generating fine nickel particles in a layer by using a plating
technique has already been disclosed (Japanese Patent Application
Laid-Open (JP-A) No. 5-303090).
[0008] However, the method requires complicated operations of
precipitating fine particles from a plating solution containing
metal ions. Moreover, processing of a waste plating solution is
also complicated and greatly affects the environment.
[0009] On the other hand, a method for manufacturing a
light-shielding film for a display that does not use the plating
technique is known. An example thereof is a technique of forming a
light-shielding film for a display by using carbon black in place
of fine metal particles (JP-A No. 62-9031).
[0010] However, carbon black has lower optical density per unit
coating amount than fine metal particles. Accordingly, when high
light-shielding property and optical density are ensured, a film
inevitably becomes thicker. Therefore, when red, blue and green
pixels are formed after formation of the light-shielding film for a
display, uniform pixels are difficult to form.
[0011] Furthermore, as another technique in which a light-shielding
film for a display is formed by using a plating technique, a method
in which a metal thin film is formed by using a vacuum evaporation
method or a sputtering method, whereby a photoresist is coated on
the metal thin film, exposed to light through a photomask having
the pattern of a light-shielding film for a display and developed,
exposed areas of the metal thin film are etched, and the resist
layer on the light-shielding film for a display is removed (See
"Color TFT Liquid Crystal Display", Kyoritsu Shuppan Co., Ltd, Jul.
20, 1996, pp. 218-220) can be used to form a film of a metal such
as chromium as a light-shielding layer.
[0012] Since a metal film is used in the method, high
light-shielding property can be obtained even if a film thickness
is small. However, since the method requires usage of the vacuum
evaporation method or the sputtering method which involves vacuum
deposition processes and etching processes, costs increase and
measures are necessary to prevent adverse influence on the
environment. Furthermore, the metal film has high reflectance, and
therefore display contrast decreases under strong ambient light. In
order to prevent such a problem, a chromium film having a low
reflectance (one made of two layers of chromium metal and chromium
oxide) can be used; however, further cost increases are
incurred.
[0013] A method for forming a light-shielding film including fine
metal sulfide particles by using plating is known (See JP-A No.
7-218715). However, since the method also uses a plating technique,
the method also has a problem of a waste solution affecting the
environment and requires complicated processes, and is therefore
unsatisfactory.
[0014] Accordingly, there is a need for an inexpensive method for
manufacturing a thin light-shielding film for a display with high
light-shielding performance.
SUMMARY OF THE INVENTION
[0015] The inventors of the invention eagerly studied in
consideration of the above need, and have found that a method in
which a coating liquid including fine metal particles and a binder
is applied to a substrate, and drying the resultant coating, can
satisfy the above need.
[0016] A first aspect of the invention provides a method for
forming a liquid crystal display comprising: providing a liquid
crystal display substrate (hereinafter simply referred to as a
"substrate"); and forming a light-shielding film for a display on
the liquid crystal display substrate by coating the liquid crystal
display substrate with a coating liquid including a binder and fine
metal particles dispersed in the binder, followed by drying.
[0017] A second aspect of the invention provides a method for
forming a liquid crystal display comprising: providing a liquid
crystal display substrate; and forming a light-shielding film for a
display on the liquid crystal display substrate by coating the
liquid crystal display substrate with a coating liquid containing a
binder, fine metal particles dispersed in the binder and a
dispersant, followed by drying.
[0018] A third aspect of the invention provides a method for
forming a liquid crystal display comprising: providing a liquid
crystal display substrate; and forming a light-shielding film for a
display on the liquid crystal display substrate by coating the
liquid crystal display substrate with a coating liquid containing a
binder, fine metal particles dispersed in the binder and a
dispersant, drying an obtained layer, forming a protective layer on
the obtained layer, and exposing the protective layer to light.
[0019] The invention can provide a thin light-shielding film for a
display with high optical density without using a plating technique
that involves complicated steps and needs measures to prevent
adverse influence on the environment and a vacuum technique whose
cost is high.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Coating Liquid Containing Fine Metal Particles
[0021] A coating liquid used in a method of the invention includes
a binder and fine metal particles dispersed in the binder, and
optionally a dispersant and a solvent.
[0022] Metal fine particles
[0023] Although there is no specific restriction on the type of
metal for the fine metal particles used in the invention,
preferable examples thereof include nickel, silver, gold, platinum,
copper and an alloy thereof. Among these, silver is more preferable
in view of chemical stability and cost.
[0024] The fine metal particles used in the invention may have
either a homogeneous or a heterogeneous composition. An example of
fine metal particles having a heterogeneous composition is one in
which a surface thereof has a coating layer having a different
composition from that of the inside thereof. Furthermore, there is
no particular restriction on forms of the fine metal particles used
in the invention, and fine metal particles with various forms such
as a sphere, an infinite form, a planar form, a cube, a regular
octahedron and a column can be used.
[0025] The average particle diameter of the fine metal particles
used in the invention is preferably in the range of 1 to 3000 nm,
more preferably in the range of 5 to 800 nm, and still more
preferably in the range of 10 to 250 nm. When the average particle
diameter is less than 1 nm, the absorption wavelength of the
particles is short. When it exceeds 3000 nm, color tint may appear
and low optical density may be obtained.
[0026] The amount of the fine metal particles included in the
coating liquid is preferably 3 to 50% by weight and more preferably
10 to 30% by weight.
[0027] There is no particular restriction on a method for
manufacturing the fine metal particles used in the invention, and
known manufacturing methods such as gas-phase methods including an
evaporation aggregation method and a gas-phase reduction method,
and liquid-phase methods such as liquid-phase reduction method can
be used. These methods are described in detail in "Choubiryusi no
gijutu to ouyou ni okeru saisinndoukou II" ("Latest Trend in
Technology and Application of Ultra Fine Particles", S.B.
TECHNO-RESEARCH CO., LTD, 2002).
[0028] Furthermore, for example, in the case of silver fine
particles (colloidal silver), conventionally known methods such as
a method for reducing a soluble silver salt in an aqueous solution
of gelatin with hydroquinone disclosed in U.S. Pat. No. 2,688,601,
a method for reducing a refractory silver salt with hydrazine
described in German Patent No. 1,096,193, a method for chemically
reducing silver ions in a solution such as a method for reducing
silver with tannic acid described in U.S. Pat. No. 2,921,914, a
method for forming silver particles by using electroless plating
described in JP-A No. 5-134358, and an in-gas evaporation method in
which a bulk metal is evaporated in an inert gas such as helium and
cold-trapped with a solvent can be used.
[0029] Dispersant
[0030] In order to prevent fine metal particles from coagulating in
the coating liquid, the fine metal particles are preferably
dispersed with a dispersant in the invention. Use of a dispersant
in the dispersion of the fine metal particles makes it possible to
obtain a light-shielding film for a display in which the fine metal
particles are well dispersed and which has high optical density.
Examples of the dispersant that can be used in the invention
include surfactants and polymers.
[0031] As the surfactants, all of anionic surfactants, cationic
surfactants, nonionic surfactants and amphoteric surfactants can be
used. However, anionic surfactants and nonionic surfactants are
particularly preferable. The HLB value of the surfactant used in
the invention cannot be generally defined, and depends on whether a
solvent of the coating liquid is a water system or an oil system.
However, it is preferably in the range of approximately 8 to
approximately 18 when the solvent is a water system, and in the
range of approximately 3 to approximately 6 in the case of an oil
system. HLB values are described in "Kaimen Kasseizai Handobukku"
("Surfactant Handbook", edited by Yoshida Tokiyuki et al.,
published by Kougakutosho Ltd., 1987).
[0032] Specific examples of the surfactants include propylene
glycol monostearate, propylene glycol monolaurate, diethylene
glycol monostearate, sorbitol monlaurate polyoxyethylene sorbitol
monolaurate, and the surfactants described in "Surfactant
Handbook".
[0033] The amount of the surfactant used is preferably in the range
of 0.01 to 30% by weight relative to the fine metal particles, and
more preferably in the range of 0.1 to 20% by weight.
[0034] The polymers used in the invention preferably have
protective colloid properties. Examples of such a polymer include
gelatin, polyvinyl alcohol, methylcellulose,
hydroxypropylcellulose, polyalkylamine, partial alkyl esters of
polyacrylic acids, and polymers described in "Ganryou no Jitenn"
("Pigment Dictionary", edited by Ito Seisirou, published by Asakura
Shoten, 2000).
[0035] The amount of the polymer used is preferably in the range of
0.01 to 30% by weight relative to the fine metal particles, and
more preferably in the range of 0.1 to 20% by weight.
[0036] Binder
[0037] Next, a binder used in the light-shielding film will be
explained.
[0038] Examples of the binder contained in the light-shielding film
in the invention include: polyvinyl alcohol; gelatin, cellulose
polymers such as methyl cellulose; and acrylic or styrene-acrylic
polymers made of any of methyl methacrylate, ethyl acrylate, benzyl
acrylate, acrylic acid, methacrylic acid, and styrene.
[0039] Among them, alkali-soluble acrylic and styrene-acrylic
polymers whose monomer(s) includes acrylic acid and/or methacrylic
acid are preferable since they enable patterning with alkali
development.
[0040] The total content of acrylic acid and/or methacrylic acid in
the monomers of the alkali-soluble acrylic and styrene-acrylic
polymers is preferably 10 to 60 mass %, and more preferably 20 to
50 mass %.
[0041] Specific examples of the acrylic and styrene-acrylic
polymers include: a copolymer made of 60 mass % of benzyl
methacrylate and 40 mass % of methacylic acid; a terpolymer made of
10 mass % of methyl methacrylate, 60 mass % of styrene and 30 mass
% of methacrylic acid; a copolymer made of 20 mass % of methyl
methacrylate, 50 mass % of styrene, 15 mass % of acrylic acid, and
15 mass % of methacylic acid; a terpolymer made of 30 mass % of
benzyl methacrylate, 35 mass % of methyl methacrylate, and 35 mass
% of methacrylic acid; and a terpolymer made of 60 mass % of
styrene, 20 mass % of acrylic acid, and 20 mass % of methacrylic
acid.
[0042] The binder may also be a monomer or an oligomer. Specific
preferable examples thereof include polyfunctional acrylic monomers
such as ethylene glycol (meth)acrylate, triethylene glycol
di(meth)acrylate, 1,3-butanediol di(meth)acrylate, tetramethylene
glycol di(meth)acrylate, propylene glycol di(meth)acrylate,
trimethylolpropane tri(meth)acrylate, 1,4-hexanediol
di(meth)acrylate, pentaerythritol hexa(meth)acrylate, and
dipentaerithritol hexa(meth)acrylate.
[0043] The polyfunctional monomers can be cross-linked with light
or heat as mentioned previously. However, it is preferable that the
polyfunctional monomer(s) is photopolymerized by using, as a
polymerization initiator, a halomethyl-S-triazine compound such as
bis[4-[N-[4-(4,6-bistrichloromethyl-S-triazine-2-yl)phenyl]carbamoyl]phen-
yl]cebacate.
[0044] The light-shielding film in the invention may further
contain a polymer to improve dispersion stability of fine
particles. Examples of the polymer (so-called "dispersant") include
polyvinyl alcohol, an acrylamide/acrylic acid copolymer, a
styrene/maleic anhydride copolymer, sodium polyacrylate, and sodium
alginate. Dispersants disclosed in "Pigment Dispersion Technique"
(written by Kazuhiro Takabo, published by Technical Information
Institute, Co., Ltd., 1999) can also be used. Among them, a
hydrophobic one is particularly preferable.
[0045] The thickness of the light-shielding film in the invention
is preferably 0.9 .mu.m or less, more preferably 0.6 .mu.m or less,
and still more preferably 0.4 .mu.m or less. Moreover, the optical
density (OD) of the light-shielding film in the invention is
preferably 3.3 or more, and more preferably 3.5 or more.
[0046] Solvent
[0047] A known organic solvent can be used in the invention.
Particularly preferable examples of the organic solvent include
methyl alcohol, isopropyl alcohol, MEK, ethyl acetate and toluene.
Furthermore, water is also a preferable solvent. These solvents can
be mixed, if necessary.
[0048] Substrate
[0049] A glass substrate used in a liquid crystal display device
and the like is preferably used in the invention. As the glass
substrates, those made of known glasses such as soda glass, low
alkali glass and alkali-free glass can be used. The thickness of
the substrate is preferably in the range of 0.5 to 3 mm, and more
preferably in the range of 0.6 to 2 mm. Those described in, for
instance, "Ekisyo Disupurei Kougaku Nyuumonn" ("Introduction to
Liquid Display Engineering", Suzuki Hanani, The Nikkan ogyo
Shinbun, Ltd., 1998) can also be used as the glass substrate.
[0050] Other Components of the Coating Liquid
[0051] In the invention, the coating liquid that contains the fine
metal particles optionally includes a polymer other than the above
polymers as a binder, a monomer, a polymerization initiator, a
polymerization inhibitor, a surfactant, and a thickener.
[0052] The coating liquid containing the fine metal particles in
the invention can be photosensitive. In order to have
photosensitivity, the coating liquid may include a photosensitive
resin composition. The photosensitive resin compositions may be
those described in JP-A No. 10-160926, paragraph Nos.0016 to 0022
and 0029.
[0053] Furthermore, when the fine metal particles such as silver
colloid are used as a water dispersion, it is necessary that the
photosensitive resin composition is water-system. Examples of such
a photosensitive resin composition include ones described in JP-A
No. 8-271727, paragraph Nos.0015 to 0023, and, as commercially
obtainable ones, SPP-M20.TM. manufactured by Toyo Gosei Co., Ltd.
Method for Manufacturing Light-Shielding Film for Display
[0054] The method of the invention includes: coating a coating
liquid including the fine metal particles on a substrate and drying
the resultant coating.
[0055] There is no particular restriction on the method for forming
the pattern of a light-shielding film for a display. Examples of
the method for forming the pattern are described below.
[0056] (1) A method in which a substrate is coated with a
photosensitive coating liquid containing the fine metal particles
to form a light-shielding layer (a layer containing the fine metal
particles), portions of the light-shielding layer other than a
pattern are removed by exposure and development, and thereby the
pattern is formed.
[0057] (2) A method in which a substrate is coated with a
non-photosensitive coating liquid containing the fine metal
particles to form a light-shielding layer, the light-shielding
layer is coated with a photosensitive-resist liquid to form a
resist layer, a pattern is formed through exposure and development,
unnecessary portions of the light-shielding layer on which the
resist layer does not exist are dissolved to form a pattern in the
light-shielding layer, the resist layer is removed, and thereby a
light-shielding film for a display is formed.
[0058] (3) A method in which a coated layer is formed in advance on
portions of a substrate other than a pattern, the substrate is
coated with a non-photosensitive coating liquid containing the fine
metal particles to form a light-shielding layer, and the coated
layer is removed along with portions of the light-shielding layer
thereon.
[0059] Coating
[0060] In the invention, there is no particular restriction on the
method for coating a substrate with a coating liquid. A spin coat
method, a curtain coat method, and an extrusion method described
in, for instance, JP-A No. 5-224011 can be used.
[0061] In the spin coat method, a coating liquid is dropped on a
rotating substrate and spread on the entire surface of the
substrate by use of centrifugal force.
[0062] The curtain coat method is one of slot orifice coating
methods also called a "flow coat method". In this method, a coating
liquid is dropped through a slit like a curtain and applied to the
substrate. Either of the slit or the substrate moves horizontally
and thereby the coating liquid is spread on the entire surface of
the substrate as an even thin layer.
[0063] The extrusion method is also called the "extrusion coat
method", wherein a coating liquid extruded from a slit is directly
spread on a moving substrate.
[0064] Details of the coating methods mentioned above are described
in, for example, "Kotingu Gijutu" ("Coating Technique", supervised
by Harasaki Yuji, published by Sogogijyutu Center, 1983).
[0065] Exposure
[0066] A light source used for the exposure is chosen according to
the photosensitivity of the light-shielding photosensitive resin
layer. Examples of the light source include known light sources
such as an ultra high pressure mercury lamp, a xenon lamp, a carbon
arc lamp, and an argon laser. As is described in JP-A No. 6-59119,
an optical filter whose transmittance is 2% or less with respect to
light having a wavelength of 400 nm or more may be used
together.
[0067] Development
[0068] As a liquid developer, a dilute aqueous solution of an
alkaline substance is used. Moreover, the liquid developer may
include a small amount of a water-miscible organic solvent. Typical
examples of the alkaline substance include alkali metal hydroxides
(for instance, sodium hydroxide and potassium hydroxide), alkali
metal carbonates (for instance, sodium carbonate and potassium
carbonate), alkali metal hydrogen carbonates (for instance, sodium
hydrogen carbonate and potassium hydrogen carbonate), alkali metal
silicates (for instance, sodium silicate and potassium silicate),
alkali metal metasilicates (for instance, sodium metasilicate and
potassium metasilicate), triethanolamine, diethanoleamine,
monoethanolamine, morpholine, tetraalkylammonium hydroxides (for
instance, tetramethylammonium hydroxide) and trisodium phosphate.
The concentration of the alkaline substance in the liquid developer
is 0.01 to 30% by weight, and pH of the liquid developer is
preferably 8 to 14. The characteristics of the liquid developer,
such as pH, can be controlled in accordance with the nature such as
the oxidation of the light-shielding photosensitive resin layer
such that development is conducted by elimination of a film
form.
[0069] Typical examples of the water-miscible organic solvent
include methanol, ethanol, 2-propanol, 1-propanopl, butanol,
diacetone alcohol, ethylene glycol monomethyl ether, ethylene
glycol monoethyl ether, ethylene glycol mono-n-butyl ether, benzyl
alcohol, acetone, methyl ethyl ketone, cyclohexanone,
.epsilon.-caprolactone, .gamma.-butyrolactone, dimethyl formamide,
dimethyl acetamide, hexamethyl phosphoramide, ethyl lactate, methyl
lactate, .epsilon.-caprolactam, and N-methyl pyrrolidone. The
concentration of the water-miscible organic solvent in the liquid
developer is generally 0.1 to 30% by weight.
[0070] The liquid developer may include a known surfactant. The
concentration of the surfactant in the liquid developer is
preferably 0.01 to 10% by weight.
[0071] The liquid developer can be used either as a bath liquid or
as a spray liquid. In order to remove non-cured portions of the
light-shielding photosensitive resin composition layer in a solid
form (preferably a film form), a method of scrubbing the
light-shielding layer with a rotating brush or a wet sponge in the
liquid developer, or a method making use of a spraying pressure
when the liquid developer is sprayed is preferably used. The
temperature of the liquid developer is preferably in the range of a
temperature close to room temperature to 40.degree. C. A washing
step can be conducted after the development process.
[0072] Drying
[0073] After the development process, a heating and drying process
is conducted. Namely, a support having a resin layer that has been
photo-cured by exposure (hereinafter, referred to as a "photo-cured
layer") is heated in an electric furnace or a desiccator, or is
heated by irradiating light from an infrared lamp onto the
photo-cured layer. The temperature and the time period of heating
depend on the composition of the polymerizable composition used and
the thickness of the formed layer. However, in general, in order to
obtain sufficient solvent resistance and alkali resistance, it is
preferable to heat at a temperature in the range of approximately
120 to approximately 250.degree. C., for approximately 10 to
approximately 300 minutes.
[0074] When a light-shielding layer is formed according to the
method of the invention, the optical density of the light-shielding
layer per .mu.m of the film thickness is preferably 1 or more.
Furthermore, in order to prevent the fine metal particles from
fusing during the heating process in preparing a color filter, the
content of the fine metal particles in the coloring composition is
preferably controlled so that the content of the metal particles
contained in the formed light-shielding layer is 10 to 90% by mass
and preferably 10 to 80% by mass.
[0075] The light-shielding film for a display obtained according to
the method of the invention has a light-shielding layer formed by
using a coating liquid containing the fine metal particles. The
thickness of the light-shielding layer is preferably approximately
0.3 to approximately 2.0 .mu.m. Since the fine metal particles are
dispersed in the light-shielding layer of the light-shielding film
for a display obtained by the invention, even when a film is thin
as mentioned above, sufficient optical density can be obtained.
[0076] The swelling degree of the light-shielding film for a
display in the invention is preferably 0.5 or less at 25.degree.
C.
[0077] The swelling degree S mentioned herein is defined as
S=(.DELTA.d-d)/d wherein d represents the dry thickness of a film,
and .DELTA.d represents the thickness of the film when the film has
been immersed in distilled water kept at 25.degree. C. for 60
seconds.
[0078] In the invention, after the formation of the light-shielding
layer and before the exposure thereof, a protective layer may be
formed on the light-shielding layer. The protective layer is
disposed to block oxygen during the exposure and to increase
sensitivity. For this purpose, the protective layer is preferably
mainly made of an oxygen-blocking resin such as polyvinyl alcohol.
Since the protective layer is unnecessary after the formation of
the light-shielding film for a display, it is removed by
development. Provision of the protective layer makes it possible to
manufacture a light-shielding film for a display with less light
exposure.
EXAMPLES
[0079] Hereinafter, the present invention will be explained in more
detail by way of examples; however, the invention is not restricted
to the examples.
Example 1
[0080] Manufacture of Silver Particles
[0081] Manufacture of Silver-Dispersed Slurry
[0082] 3,488 g of distilled water was added to 112 g of gelatin,
and the resultant mixture was heated to approximately 47.degree. C.
to dissolve the gelatin. 4.0 g of calcium acetate and 2.0 g of
potassium borohydride were added to the mixture. Immediately after
that, a solution made of 6.0 g of silver nitrate dissolved in 1.0
liter of distilled water was rapidly added to the mixture while the
mixture was stirred. Distilled water was also added to the
resultant mixture to make the total weight of the resultant 5.0 kg.
Then, the resultant product was cooled down at a temperature close
to a gelation temperature and immersed into cooled water through
small holes, and thereby very minute noodle-like materials were
formed. These noodle-like materials were supplied as an amplifying
catalyst to generate blue silver in a field. For convenience's
sake, and in order to prevent the noodle-like materials from
forming a fused mass, water was added to the noodle-like materials
so that the ratio of water to noodle-like materials became 1:3.
[0083] A solution made of 6.5 g of potassium hydroquinone
monosulfonate and 0.29 g of KCl dissolved in 81 g of distilled
water was added to 650 g of borohydride reduced silver nucleus. The
slurry containing the noodle-like materials was cooled down to
approximately 6.degree. C. The following solutions A and B were
manufactured in separate vessels.
[0084] A 19.5 g of sodium sulfite (anhydride)
[0085] 0.98 g of sodium bisulfite (anhydride)
[0086] 122.0 g of distilled water
[0087] B 9.75 g of silver nitrate
[0088] 122.0 g of distilled water
[0089] Solutions A and B were mixed, forming white precipitates
that disappear when stirring is continued. Immediately after that,
the mixture was rapidly added to the slurry including the
noodle-like materials for a short period of time (5 minutes or
less) while the slurry was stirring. The temperature of the
resultant mixture was kept at 10.degree. C. and amplification was
allowed to proceed for approximately 80 minutes until all soluble
silver salt was reduced on the nucleuses. The resultant blue slurry
particles were made to pass through tap water in the form of a
slurry in a nylon mesh bag and washed so that washing water passed
through the bag for approximately 30 minutes. As a result, all
salts could be washed away. In order to obtain a blue silver
dispersion containing silver in a concentration of 1.5% by weight
when melted, the washed blue silver dispersed in the gel slurry was
drained until the total weight of the product became 412 g.
[0090] Manufacture of Silver Fine Particles
[0091] Six grams of a dispersant (Rapisol B-90 manufactured by
Nippon Oil & Fats Co., Ltd.) and 2000 g of a 5 wt % aqueous
solution of papain were added to 4000 g of the thus-obtained slurry
in which silver was dispersed, and the resultant dispersion was
stored at 37.degree. C. for 24 hours. The dispersion was
centrifuged at 2000 rpm for 5 minutes to precipitate the silver
fine particles. After discarding a supernatant, the precipitate was
washed with distilled water to remove a decomposed substance of
gelatin decomposed by enzyme. Subsequently, the silver fine
particle precipitate was washed with methanol and dried.
Approximately 60 g of aggregates of the silver fine particles were
obtained. Fifty three grams of the aggregates and 5 g of a
dispersant (Solsperse 20000 manufactured by Avecia KK) were mixed
with 22 g of methyl ethyl ketone. 100 g of 2 mm glass beads was
blended with the resultant mixture and the resultant was dispersed
for 3 hours with a paint shaker. Thus, a silver fine particle
dispersion liquid A-1 was obtained.
[0092] Manufacture of Light-shielding Layer Coating Liquid
[0093] The following substances were added to and mixed with the
silver fine particle dispersion liquid A-1, and thereby a
light-shielding layer coating liquid was obtained.
1 Silver fine particle dispersion liquid A-1 40.0 g Propylene
glycol monomethyl ether acetate 40.0 g Methyl ethyl ketone 37.6 g
Surfactant (F176PF, 20%) 0.1 g Hydroquinone monomethyl ether 0.001
g Dipentaerythritol hexacrylate 2.1 g
Bis[4-[N-(4,6-bistrichloromethyl-s-triazine-2- 0.1 g
yl)phenyl]carbamoyl]phenyl]sebacate Manufacture of Protective Layer
Coating Liquid Polyvinyl alcohol (PVA205 manufactured by Kuraray
Co., 3.0 g Ltd.) Polyvinyl pyrrolidone (PVP-K30 manufactured by GAF
1.3 g Corporation) Distilled water 50.7 g Methyl alcohol 45.0 g
[0094] The integrants mentioned above were mixed and thereby a
protective layer coating liquid was obtained.
[0095] Coating of Coating Liquid
[0096] A glass substrate was coated with the light-shielding layer
coating liquid by means of a spin coater, and the resultant layer
was dried at 100.degree. C. for 5 minutes. Subsequently, the dried
layer was coated with the protective layer coating liquid by use of
the spin coater so that a dry film thickness was 1.5 .mu.m, and the
resultant layer was dried at 100.degree. C. for 5 minutes.
[0097] Exposure and Development
[0098] The resultant was exposed to light from an ultra high
pressure mercury lamp at 70 mJ/cm.sup.2 from the coated surface
side. Then, the resultant was developed (33.degree. C., for 20
seconds) with a liquid developer TCD (an alkali developer
manufactured by Fuji Photo Film Co., Ltd.,), and thereby a
light-shielding film for a display was obtained.
[0099] The light-shielding film for a display thus obtained was
evaluated as follows.
[0100] Measurement of Film Thickness
[0101] The thickness of the light-shielding film for a display was
measured according to the following method. A specimen which was
coated with a light-shielding layer was exposed to light from the
ultra high pressure mercury lamp at 70 mJ/cm.sup.2 from the coated
surface side, and the film thickness of the specimen was measured
with a stylus-type surface roughness measuring device P-1
(manufactured by TENKOP Corp.).
[0102] The thickness of the specimen was 0.4 .mu.m.
[0103] Measurement of Swelling Degree
[0104] The specimen which had been used in the measurement of the
film thickness was immersed in distilled water at 25.degree. C. for
60 seconds, and then moisture on the specimen surface was wiped.
Thereafter, the film thickness (.DELTA.d) of the specimen was
measured by the above method. From the obtained film thickness
before immersing (dry film thickness d) and that (.DELTA.d) after
immersing, the swelling degree S (=(.DELTA.d-d)/d) was calculated,
which was 0.04.
[0105] Measurement of Optical Density
[0106] The optical density of the film was measured according to
the following method. A light-shielding layer formed on a glass
substrate was exposed to light from an ultra high pressure mercury
lamp at 70 mJ/cm.sup.2 from the coated surface side. Then, the
optical density (OD) thereof was measured with a Macbeth
densitometer (TD-904 manufactured by Macbeth Corp.). The optical
density (OD.sub.0) of the glass substrate was separately measured
by the same method. The value obtained by subtracting OD.sub.0 from
OD was regarded as the optical density of the film.
[0107] The optical density of the specimen was 3.6.
Example 2
[0108] A light-shielding film for a display of Example 2 was
manufactured in the same manner as in Example 1, except that a
protective layer was not formed on a light-shielding layer.
[0109] The film thickness and optical density of the
light-shielding layer of the specimen were 0.4 .mu.m and 3.6,
respectively. Furthermore, a light-shielding film for a display
could not be formed on the specimen through exposure of 70
mJ/cm.sup.2 with the ultra high pressure mercury lamp, but a good
light-shielding film for a display could be formed through exposure
of 500 mJ/cm.sup.2.
Example 3
[0110] A silver fine particle dispersion liquid A-2 was prepared in
the same manner as the preparation of the silver fine particle
dispersion liquid A-1, except that Solsperse 20000 (dispersant) was
not used during the dispersion of the silver fine particles. A
light-shielding film for a display of Example 3 was manufactured in
the same manner as in Example 2, except that the silver fine
particle dispersion liquid A-2 was used in place of the silver fine
particle dispersion liquid A-1.
[0111] The film thickness and optical density of the specimen were
0.4 .mu.m and 3.3, respectively. Furthermore, a light-shielding
film for a display could not be formed on the specimen through
exposure of 70 mJ/cm.sup.2 with the ultra high pressure mercury
lamp, but a good light-shielding film for a display could be formed
through exposure of 500 mJ/cm.sup.2.
Example 4
[0112] A light-shielding film for a display of Example 4 was
obtained in the same manner as in Example 1, except that a curtain
coater was used under the following conditions in place of the spin
coater.
[0113] Slit shape: length of 18 cm and width of 0.2 mm
[0114] Distance between slit and substrate: 2 cm
[0115] Substrate movement speed: 30 cm/min.
[0116] The film thickness and an optical density of the
light-shielding layer of the specimen were 0.4 .mu.m and 3.7,
respectively. Furthermore, a good light-shielding film for a
display was obtained when the exposure was conducted at 70
mJ/cm.sup.2 with the ultra high pressure mercury lamp.
Example 5
[0117] A light-shielding film for a display of Example 5 was
obtained in the same manner as in Example 1, except that an
extrusion coater similar to that described in JP-A No. 10-286507
was used in place of the spin coater.
[0118] The film thickness and optical density of the specimen were
0.4 .mu.m and 3.7, respectively. Furthermore, a good
light-shielding film for a display was obtained when the exposure
was conducted at 70 mJ/cm.sup.2 with the ultra high pressure
mercury lamp.
Comparative Example 1
[0119] A light-shielding film for a display of Comparative Example
1 was manufactured in the same manner as in Example 1, except that
the following carbon black dispersion liquid B-1 was used in place
of the silver fine particle dispersion liquid A-1.
[0120] Carbon Black Dispersion Liquid B-1
[0121] 2.5 g of carbon black (Regal 400 manufactured by Cabot
Corporation), 5 g of a dispersant (Solsperse 20000 manufactured by
Avecia KK) and 16.4 g of methyl ethyl ketone were mixed. 100 g of 2
mm glass beads was mixed with the resultant mixture and the
resultant was dispersed for 3 hours with a paint shaker, and
thereby a carbon black dispersion liquid B-1 was obtained.
[0122] The film thickness of the light-shielding layer of the
specimen was 0.4 .mu.m, but the optical density of the layer was
0.7, which was insufficient as a light-shielding film for a
display.
* * * * *